So I recently replaced my stock HU so I could hook up my new front component speaker with a 2 channel amp. I already had a mono amp and sub in my car that I cant get to work with the new HU (it's a Pioneer fh p8000 bt). I am somewhat sure everything is wired correctly (the comps do work just not the sub) and I think I have all of the HU setting correct for subwoofer output according to the manual. The sub's amp is on and everything but I might be overlooking something. I am looking for any troubleshooting advice or maybe somebody has experience with my HU. Thanks!